THIS IS US -- Pictured: "This Is Us" Key Art -- (Photo by: NBC)

For three years, viewers have tuned in every Tuesday night to catch up with the Pearsons. This week, “This Is Us” returned for a fourth season that promises more emotion and drama and plenty of surprises.

The fourth season premiere is aptly titled, “Strangers,” and begins with Rebecca (Mandy Moore) and Jack (Milo Ventimiglia) freshly returned from their thwarted cross country adventure. Rebecca muses that it’s funny how she and Jack have only known each other a few weeks and now he is so important to her. She goes on to say that so often in life, a stranger can just show up and suddenly become part of your story.

This is how Dan Fogelman chose to introduce the new characters that will soon become part of our story. A soldier (Jennifer Morrison) returns home from war with the emotional scars to prove it. A teenage father (Asante Blackk) struggles to balance his new responsibilities. And a blind young man (Blake Stadnik) meets the love of his life in a diner.

THIS IS US — “Strangers” Episode 401 — Pictured: Asante Blackk as Malik — (Photo by: Ron Batzdorff/NBC)

These introductions could be off-putting for fans who have waited all summer to find out what’s up with Kevin and Kate and Randall, particularly since each season traditionally opens on their birthday. Instead, we get to learn a little about these strangers, juxtaposed with the first time Rebecca introduced Jack to her parents.

Who those strangers are and how they fit in with the Pearsons will be revealed in due time. But their introductions, orchestrated by Fogelman and episode director Ken Olin, open the world of this series ever so slightly. For a family so close knit and often co-dependent, it is good to remember that there are other people out there, and their stories matter too. After all, Miguel and Toby and Beth and Déjà were once strangers. And now we couldn’t imagine the Pearsons or “This Is Us” without them.

THIS IS US — “Strangers” Episode 401 — Pictured: (l-r) Blake Stadnik as Jay, Auden Thornton as Lucy — (Photo by: Ron Batzdorff/NBC)

Of course we do still get glimpses of Kevin (Justin Hartley), Kate (Chrissy Metz) and Toby (Chris Sullivan), Randall (Sterling K. Brown) and Beth (Susan Kelechi-Watson). It is the Big Three’s birthday, after all. We learn just enough to know that life has moved forward fairly well over the past three months.

While this might not have been the welcome back fans were expecting, it still felt like the series we all know and love. One of the reasons “This Is Us” is so compelling is the way it always manages to tap into the emotions we need, exactly when we need them. It does so in ways that feel real and not manufactured. The tears shed week after week are genuine because everyone involved is sincere and honest.

With an impressive seven acting nominations for the third season, in addition to a nod for Outstanding Drama Series, “This Is Us” has spent three years building toward the complete story of the Pearsons. Some of the mysteries introduced in the premiere were answered by episode’s end. But, naturally, that just leads to more questions. And whatever comes, we are along for what is sure to be another great season for one of TV’s best series.

“This Is Us” airs on NBC Tuesday nights at 9ET/8CT.

GRADE: (★★★½)

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